How they work

Sealers, I’ve discovered since starting this site, are one of the most misunderstood products used for tile and stone. There are so many different brands, types and uses that it’s difficult to figure out what you actually need for your particular installation. So I’m gonna try to clear some of that up for you.

This will only cover a very small portion of the entire market for this type of product. I’m going to explain the different basic types of sealers and how they work, as well as the proper use for most common installations. This is NOT an all-encompassing article and will not include every scenario and installation. It is only a basic instruction on different types and uses.

Be sure to research any specific product you choose to utilize and always – ALWAYS – test the product first on a spare piece of your tile or stone to ensure you will not run into any incompatibility issues.

As with any product recommendation around here all opinions are mine and mine only, you will have your own and others may have different ones. I use what I know works for me – your installation may require something different. It is impossible for me to cover every scenario – so I won’t try. Feel free, however, to ask any questions and I’ll do my best to give you an accurate answer.

The above is something I feel necessary to state because we are playing with chemicals here, potentially dangerous stuff if misused. So drink AFTER you play with the chemicals – mmm’kay? (Beer or adult beverages – never drink the sealers, even when you’re done…)

What is a sealer?

I think a large part of the misunderstanding stems from the name of the product itself – sealer. People see the word sealer and assume it can be used to waterproof tile and stone – why use waterproofing substrates? If my shower is leaking can’t I just soak the tile with sealer and fix it?

No. And don’t laugh – I get those questions weekly. Sealer is not manufactured to waterproof. It does not make your tile or stone waterproof. It WILL, to an extent, make it water-resistant, but not waterproof.

Sealer is manufactured to prevent staining agents from entering the pores of the tile or stone. That’s it. It prevents staining and helps make your installation much easier to clean. Cherry Kool-Aid? It can help with that (even though it’s made with toxic waste).

It does this by entering the open pores of the tile or stone (where there would otherwise be the cherry stuff) and, once cured, forms a seal in those pores to prevent anything else from entering them.

Sounds simple enough, right? It is. Well, it is once you understand how they work.

Coatings and Sealers

There are two types of ‘sealers’ commonly sold. One is a topical sealer, which is technically not a sealer – it’s a coating, and the other is a penetrating, or impregnating, sealer.

A topical sealer, or coating, sits on top of the tile or stone and blocks all the nasty stuff by forming a shield, of sorts, over the face of the tile.

I do not like coatings.

Coatings wear unevenly. It will wear more in the traffic lanes, where you walk, and dissipate and eventually be gone. Once this happens you must strip the entire installation and install a new layer. You cannot simply reapply more of this sealer to the areas in which it has worn out. It is also not as effective, in my opinion, as a penetrating sealer.

A coating sealer is normally used on natural clay tiles such as Saltillo and Mexican pavers.

A penetrating, or impregnating, sealer on the other hand, actually enters the pores of the stone and, once cured, will not change the look of the tile or stone. It is specifically made to not alter the look of your installation while still protecting it.

It can be spot sealed, which means you can apply more to only one specific area without worry. To reseal or apply more you do not need to strip the existing sealer. It’s a better option and the one that should be used in most residential installations.

Carriers

In order to get the chemicals into the pores there must be what is called a carrier attached to the sealer. This allows the silicone or fluoropolymers (I’ll cover these in a moment) to penetrate the pores of the stone and cure below the surface to allow better resistance to staining. The deeper the penetration the better the protection.

There are two types of carrier: water or solvent. So your sealer will be either water-based or solvent-based. Solvent-based sealers will penetrate deeper into the tile or stone.

Solvent molecular structures are smaller than water molecules. It’s that simple. When using a sealer the carrier carries it into the pores then dissipates leaving behind the protection layer.

So you must take into consideration the penetrating power of the sealer as well as the dissipation rate (water evaporates more slowly) which can be affected by temperature and humidity factors. Water-based sealers have a limited window of temperature with which they can be used – solvents have a much larger window.

It is my opinion that a solvent-based sealer is normally always the best option. Which brings us to the part everyone freaks out about…

VOC’s

VOC stands for volatile organic compound. They are organic chemicals with a high vapor pressure. This simply means that they cause large numbers of molecules to be released into the air (vapors) as it dissipates or evaporates. Research indicates that VOC’s will negatively affect the ozone layer. I’m sure everyone has heard of VOC’s.

One highly misunderstood (or ignored) fact is that VOC’s only react with the ozone. They do NOT negatively affect your skin, health, breathing, etc. over the long-term. You will smell it for a while before it dissipates, and it can cause you discomfort, dizziness, etc. It’s meant to, it tells you to get away from it until it dissipates. But long-term effects from short-term exposure do not exist. It is temporary.

Certain chemicals in any sealer may negatively affect these things (read the msds and product sheets), but VOC’s ONLY affect the ozone layer, that’s it. Always wear a mask and gloves when handling these chemicals! But again, it is not a permanent condition.

VOC does not equal toxicity! If something has a higher VOC count that only means that it interacts with the ozone more than a product with low VOC. It has nothing to do with your health, air quality in your home, etc. Again! Individual ingredients in a product may have these effects, the fact that a product has VOC’s does not indicate that it will. Water-based sealers also contain VOC’s, just less of them than a solvent-based sealer.

Once the sealer cures these VOC’s no longer exist! They do not continue to ‘off-gas’ as some stones do, which you may have read about, nor do they continue to dissipate forever. Once it’s cured they’re gone.

This is a subject for a different post, I just want to make sure you don’t associate VOC count with any type of negative health effect or home air quality. I point this out because a lot of solvent-based sealers may have higher VOC counts than water-based or a lower quality solvent-based sealer. It will not negatively affect your health or home. Again, read the msds sheets and product literature.

I’m unsure how to word this exactly to get my point across. It will smell, it will make you dizzy if you inhale enough of it. But these conditions are temporary and do not lead to long-term effects. Again, VOC does not equal toxicity.

Protection sources

Protection sources are the base product in the sealer – what the carriers are carrying. The base protection source will determine what the sealer will protect against. There are two different main sources – silicone and fluoropolymers.

Silicones protect and seal against water-based staining agents – the aforementioned cherry Kool-Aid, for example, coffee, tea, etc.. It is just like the silicone in the tubes you use to seal your corners – same principle.

They will not completely prevent absorption into the surface! They will, however, slow the absorption enough that you can get it cleaned up without staining the stone in a reasonable amount of time. Silicone sourced sealers are a base sealer to prevent regular water-based stains on your tile or stone (or grout).

All fluoropolymer sourced sealers, to my knowledge, are solvent-based. Fluoropolymer sealers also have limited water-based stain repellent properties, they will repel water-based stains as well as oil-based. Not as effectively as silicone sourced sealers, but to some extent.

Bored yet?

So to wrap-up a bit, the sealer you choose must match your installation requirements. This is why it’s difficult for me to give a general answer to “what sealer should I use?” It depends on what you need your sealer to do.

For most residential applications, which is what I do, I use a penetrating solvent-based fluoropolymer sealer. Depending on the particular type of tile or stone I’ll normally use Miracle Sealant’s 511 Impregnator or Miracle Sealant’s porous plus.

If you read anything on my site you’ll get the feeling that I’m a die-hard Laticrete fan. That’s accurate. I’m just as zealous about Miracle Sealant’s sealing and care products. I think they’re superb! (Did I really just type ‘superb’??? I need a beer Pepsi…)

So which of those should you use with what types of tile or stone? That is the subject of my next post, I’ve already bored you enough with this one. Next time we’ll cover more in-depth uses and needs as well as what works with which tile.

Should you apply the sealer to natural stone before laying it? If so, do you seal 5 surfaces (top and 4 sides)? Or do you install the tile and seal before grouting? Then, of course, you seal the tile and grout when the job is complete…right?
And which sealer do you prefer for travertine and limestone for bathroom floors and showers?
Thank you.

I’m confused about tile & stone sealers vs grout sealers. We need to reseal our porcelain mosiac tile shower floor. The original grout used was an Unsanded grout. It was originally sealed with Miracle seal 511 Spray-On Grout Sealer . What is the best method, sealant, to reseal the floor? I don’t want to reseal the floor every year if possible. Thanks

Hi Randy,
You do not need to seal porcelain. If you want to reseal the grout any good tile sealer will work. The only thing that wears out sealer is abrasion, water will do that. There is no way about it. A good penetrating sealer, however, will last a lot longer than a year. Any type of spray on sealer is not that, or not. It needs to sit on the surface to absorb before being buffed off. Use regular 511.

Hi. I need to reseal my saltillo floor. I believe it has a topical water based seal. It does not wear well in high traffic areas and stains easily.
Could you recommend a solution? For instance, strip old sealer and reapply a penetrating sealer? Or reapply another topical sealer? Brands?
Thanks!

You will need to strip the old sealer. If you don’t anything you put on it will still show that wear pattern. I believe you need to use a topical coating of some sort on saltillo (not positive – I NEVER work with it around here). Your best bet is to call the tech line at whatever manufacturer you choose. I prefer miracle sealants brand. Their tech line number is 1-800-350-1901 ext. 1.

Hi Roger,
Just found you site and it is fantastic and thank you for it. Husband is doing tiling projects and now I want out customers to be happy and stay that way obviously. My question. He hates sealing tile, spectraloc is not available around here and now I have to seal the tile. I have severe chemical sensitivities. That being said, you love the fluoropolymer solvent sealers and I probably won’t be able to use them. Do the silicone based sealers stink as bad? or you have a recommendation for a brand of fluoropolymer that doesn’t stink to high hell? I can deal with a little vapour, but in a small bathroom even with the exhaust running I will probably get pretty sick. Thanks a bunch!

Hi I am having an issue with my grout in my tub/shower surround. Just installed white porcelain subway tile with an unsanded dark gray grout a little over a week ago. The grout dried lighter than the package showed and looks hazey in areas. I’ve been cleaning with a vinegar/water solution and it’s starting to even out a little, but still looks too light. When wet, it’s beautiful. I was hoping to use a solvent based enhancer and sealer to darken it some but was told that is not recommended for a shower area since a lot of water is hitting it, causing it to become even lighter over time..is this true? Your advise is much appreciated!

Have you ever used MegaSealed? It is a product made in Austrailia and is used to stop tiled shower floors from leaking. They give a 25 year warranty and using this product prevents having to rip out the shower floor if the shower pan or membrane is compromised. I would think there would be a similar product in the USA but I cannot find it. Do you have a suggestion?

Hi,
I am about to tile my bathroom floor. The tile I bought needs to be sealed before grouting. Do I lay them in thinset let them dry, then seal, then grout or seal them before I even put them on the floor? Could the thinset ruin the finish also?

I have light beige tiles on my shower walls. After a few weeks of using the shower the bottom tiles on the wall get a dark wet look. I have had it checked out by the plumbing contractor who used a camera to look for any leaks. He found no problem. Could water be absorbed through the grout and turn it dark? When I do not use the shower, it dries up and looks fine. If a seler is necessary, what kind should I use?

You did not mention if this was over a tub or tiled shower floor. If over a tub make sure you have proper weep holes so the water can drain. Water will ALWAYS get behind your tile. Sealer has absolutely nothing to do with that.

Have stone on my shower floor sealed with two applications of Surface Guard max strength sealer. The area just below shower head turns dark after getting wet. It eventually returns to “normal” if the shower isn’t used for a few days. The shower did have slow drip for a few days before installation was complete. Is it possible that it wasn’t totally dry before I sealed it? If so, how do I remedy this? Thanks for any help you can suggest.